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L. H. BURNHAM.

TRANSFORMER. APPLICATION FILED JAN-29; H117- Patented May 20, 1919.

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. UNITED STATES PATENT OFFICE.

LOCKE H. BURNHAM, OF PITTSFI'ELD, MASSACHUSETTS, ASSIGNOR TO GENERALELECTRIC COMPANY, A CORPORATION OF NEW YORK.

TRANSFORMER.

' Specification of Letters Patent.

Patented May 20, 1919.

7 Application filedianuai'y 29, 1917. Serial No. 145.131.

To all Mam it may concern:

- auto-transformers or compensators, some 'thereo reactances, etc. Itparticularly relates to suchdevices of the so-called core type andsimilar forms in which considerable portions of the external surfaces ofthe windings are exposed to the influence of a cooling fluid, andpreferably are arranged to be cooled'bythe forced flow of the coolinglfluid. Some of the objects of my invention 20.

are to improve the cooling or ventilating of such afparatus, andincrease the capacity The increase in capacity is secured by bettercooling or ventilation. v

I accomplish the objects ofmy invention by requiring the cooling fluidto flow in thorough contact with the transformers, or at least thewindings thereof, preferably in directions generally parallel to theextent of the core legs, and preferably by means of casings or barriersfairly closely and unithe parts to be cooled for directing the owof thecooling fluid thereover; preferably the "casings or barri'ersare used'in combination with means for forcing the flowof the coollng fluid.

The casings or barriers of. my nvention 1 may be employed fwithmanytypesof wind;

.ings, but it isnotable .that'usm such casings or barriers with wmdm s oseparatedv 4 0.

disk coils, with which type 0 winding such direction. of fluid flowas'is-obtained by my invention would seem to'ha've' little promise, Ihave secured quite surprisingly sat1sfa c-' to? results usi'n air as thecoolmg fiu1d an 'I forcing the ow1thereof.

In the accompanying lowin description I ave illustrated and descri ed insome detail certain preferred embodiments ofmy invention in transform-"ers of the core type, from which m invention may be more completely unerstood.

Figure 1 is an elevation artly in section of an air blast concentricdiskcylindrical coil inventiona. Fig. ,2 is an elevation partially insection of drawings and fola concentric cylindrical '-coi|l transformeralso embodying my invention. Fig. 3 is a plan view of the transformer ofFig. 2. Fig.4 is an elevation also partially in section of aninterleaved disk, coil transformer embodying my invention; this figurealso illustrates a casing about a transformer and provided-withventilations for governing the amount of coolingfluid flowing throughthe transformer. In all the figures the transformers are shown in verysimple form, all

Within the'cylindrical coil 8 and spaced therefrom and from the core leg6 is a cylinder or barrier 11 of insulating material for .both assistingin the insulation of thecoilB from the core leg'6 and for directing andproportioning the air fiowin over the core leg6 and over the inner surace of the coil 8. Likewise between the coil 8 and the disk coils 9, andseparated fromall these coils,

is a similar cylinder or barrier 12 likewise assisting in the insulationof the coil- 8 and prpportioning the air to the inner edges of the diskcoils 9 and to the outer surface of the coil 8. An inclosing casing orbarrier 13 dis osed close to theouter edges of the disk coi 9substantially surroundsv and is substantially uniformly spaced from theentire circumferences of the windings on both the core legs 6 and 7. Theshape of this casing 13 in plan more clearly appears in- Fig. 3. It willbe understood that the windings and internal cylinders or barriers onthe core 1e 7 are similar to those on the core leg 6. T e coils. andinsulating casings and bar-.'

.riers (that 'isll, 12 and 13) are spaced from each other by anysuitable. spacers providing for the-exposure of so much of the coilsurfaces, faces and edges, to the flow of thecooling air as possible,the ventilating.

' spacer or :passages adjacent the barrier be; ing preferably parallelto the winding-axis.

Surrounding the lower yoke of the core 5 is a receiving compartment orcasing 15 resting directly on the fioor 16 carrying the transformer. Thetop of this receiving casing .15 is provided with an opening of the sameshape as the plan of the casing 13 and the casing 13 sets into thisopening, the sides of the casing being joined to the. edges of thisopening as appears from Fig. 1.

The lower end of the receiving casing 15 is open to the flooropenings 17through which air is forced into the transformer through the passage 18from the compressor or blower 19.

7 As may be observed from Fig. 1 and the above description, air from theblower 19 is forced to flow through the passage 18 and the openings 17into the receiving casing 15, and from thence vertically upward withinthe casing or barrier 13 until it escapes to the atmosphere above theupper end of the casing 13. In its passage upward air from the receivingcasing ,is directed into thorough contact with the outer edges of allthe disk coils 9 by means of a casing-or barrier 13, this casing orbarrier being preferably sufliciently closely placed to the edges ofthese coils to secure this result. Furthermore this air is brought 'intosubstantially thorough contact about substantially the entirecircumferences of the windings by reasonof the peculiar shape 'of thecasing-13 .(as appears from Fig. 3) whereby the casing 13 issubstantially uniformly spaced from the exteriors of the windings whichin this-case are the parts of the transformer particularly to be cooled;Other portions of the air comin into the receiving casing 15 pass upwardetween the inner edges of the coils -9 and the outer surfaces of thecylinders 12, between the-inner surfaces of e cylinders 12 and the innersurfaces of the coils-8, between the inner surfaces of the coils 8 andthe outer surfaces of the vcylinders 1'1 andbetween the inner surfaces.of the cylinders lland the outer surfaces of the core legs. Undoubtedlythere is more or less circulation of the cooling fluid between, thecoils 9 for some distances from their edges. The cylinders 11 and 12 areplaced as close to the-adjacent coils as is necessary to secure the mostefficient cool ing of the windings so far as the other con- .ditions ofthe transformer allowor justify;

the spacing of the casing 13 from the winding surfaces can depend moreupon the efiiciency of cooling to be secured thereby-.- If the casingswhich direct the flow of the cool ing fluid are disposed too closely tothe parts to be cooled thereby, the amount of cooling or the economy ofa given'heat loss:

is less than 'it need-be, and likewise if the casings. are too farmovedthe same efiects "are experienced. If the casings or barrierscooling are properly disposed, however, elficient is developed. I havefound that disposlng the casings about a toof 'an the windings inchradially from the circumference of the windings gives very satisfactoryresults when the cooling fluid is air and is forced through theapparatus. It will be understood of course that this spacing will varywith the different constructions. The casings or barriers are preferablysubstantially uniformly spaced from the parts to be cooled, in the caseillustrated from thewinding circumference, in order that those parts maybe uniformly cooled.

In F ig. 2 the transformer is likewise the core type, but the windingsare of the concentric cylindrical type. In this transformer there arelikewise three barriers bearing the same reference characters as the.

three barriers of Fig. 1. Likewise there is a receiving casing 15 openat the bottom as before. The spacers 21 for spacing the coils andbarriers are illustrated in this figure, and also in Fig. 3 which is aplan view of the same transformer.

' The transformer of Fig. 4 is of the interleaved disk coil type. Likethe transformers of the preceding figures this transformer is providedwith an inclosing casing or barrier 41 (which in plan is like the casing13 of Fig. 3), and in addition is provided with a casing 42,, totallyinclosing the transformer and the casing or barrier 41' and providingthe exterior surface of the device. The

casing 42 is provided in its cover with a number of openings which maybe more or less closed by adjustable leaves 43. There is coils from eachother as necessary, and pre erably are separated from the coil faces toallow access of the cooling fluid to those faces. Suitable spacers maybe used to maintain the proper spacing between the barriers, insulatingplates and coils, such spacers being separated from each other to rovideventilatmg passages and spaces as 'efore indicated. While the inclosingcasing 41 generally conforms in plan to the casing 13 of the precedingfigures, the casing 42 may be of substantially any desired shape'inplan. This latter is allowable since the casing 41. closely and uniformlrounds the windings and-directs the ow of the cooling fluid in throughcontact with derstood o for the transformer of Fig. 4 enters the andcorelegs. It will be uncourse, that the cooling fluid transformeradjacent one yoke and leaves adjacent the other, the entire flow beingwithin the casing 41 and preferably upward. The cooling fluid leaves thecasing 42 below the leaves 43.

I am aware that it has been heretofore,

proposed to use barriers or casings about whole transformers, and evenabout indi vidual parts of transformers, which to some I intended only 5for water coils, etc.

extent direct the flow of the cooling fluid something likeparallel tothe winding axis. However,so far as I am aware, these barriers andcasings have beendisposed quite differently than the barriers or casingsof:

my invention; so in; as I am aware there hasbeen no realization of theadvantages of disposing the barriers or casings in the man-v ner Ipropose, that is so that substantially the. whole of the cooling fluidis forced to flow in thorough contact with the parts of the transformersto be cooled. The prior known barriers or casings seem to have been fromthose of my invention, as preventing eddy currentsin the cooling fluid,separat ing the cooling'fluid into 'tWo bodies so that the fluid itselfis more efliciently cooled, separating the cooling fluid into two ormore portions as one 'for cooling the coils and another portion forcooling the core, for

eflectually directing the cooling fluid into contact with the coolingmeans therefor as disposed without the. consideration of their effectwhich is particularly the subject of my invention, that is, directingthe flow of the fluid into direct contact with all the transformer partsto be cooled by the fluid flow. My invention therefore distinguishedfrom ;such prior constructions.

While I: have described the principle of my invention and the best modeI have contemplated for'applying this principle, othermodifications'will occur to those skilled in this art and I aim in the aended claims to cover all modifications w ichdo-not involve a departurefrom the spirit and scope of my invention. v What I claim as new anddesire to secure by Letters Patent of the United States, is:

1. The combination with a core, of a plurality of coiled windings'coaxially mounted to surround a legof .said core, meansfor supplying astream ofa cooling and insulating medium to said windings, and meansrelatively close to the edges of said wind ings for causing said streamto be divided intocurrents moving substantially parallel.

' to the windingaxis and passing over both the inner and outer edges ofsaid windings. 2. The combination with a casing having a core therein,of a plurality of coiled windings coaxially mounted to surround aleg ofsaid core, means for suppl'yina stream of a cooling and insulating m iumto said urposes quite difl'erent To carry out these pur-- poses, thebarriers and casings have been windings, and means relatively close tothe edges of. said windings for causing said stream. to be divided intocurrents moving mined distance from the edges of said windings andadapted to divide said stream into currents 'movi'ng substantiallyparallel to I the Winding axis and passing over both the inner andouteredges of the windings; said casing having an outlet for the unitedcurrents. v

4. The combination with .a casing having.

a core therein, of a plurality of coiled windings coaxially mounted tosurround a leg'of a cooling and insulating medium to said windings, andinner and outer cylindrical barriers spaced a predetermined distancefrom the-respective inner and outer-edges of said windings arranged todivide said stream into currentsmoving substantially parallel to thewinding axis and passing over the ed es of said windings; said casingbeing provided with a common outlet for the united currents. 5. Thecombination with a casing having said core, means -for supplying astream of a core therein, of a plurality of COilBdJNiIld- I ingscoaxially mounted to surrounda leg of said core, a receiving compartmentadjacent one end of said casing, means for supplying a cooling andinsulating medium to said compartment, means close to but spaced apredetermined distance from both. the inner andouter edges of saidwindings for dividing the medium in said compartment intocurrentsmoving-parallel to the windlng axis and over the edges of saidwindings; said currents emerging from the casing as a reunited stream.

6. The combination with a casing having 7 a core therein, of a pluralityof coiled windings coaxially mounted to, surround a leg of one end ofsaid casing, cylindrical barriers placed adjacent to'but a predetermineddistance from the edges of said windings and arranged to divide themedium supplied to said compartment into a plurality of currents movingsubstantially parallel to'the.

'said core, a receiving compartment adjacent winding axis andover boththe inner and outer edges of said windings; said casing having a commonoutlet for the emerging currents.

.7.-The combination with a casing having a core therein,'of a pluralityof coiled windings coaxially mounted to surround a leg of said core, areceiving compartment adjacent one end of said casing, open endedbarriers projecting into said compartment and spaced a predetermineddistance from the edges of said windings, said barriers arranged to haveone end divide the medium supplied to said compartment into a pluralityof currents moving substantially parallelto the-winding axis and overboth the inner and outer edges of said windings; said casing having acommon discharge for the currents emerging from the other end of saidbarriers; I I

8. The combination with a casing having a core therein, of a pluralityof disk coils arranged coaxially on a leg of said core,

insulating collars interleaved with said coils,

a receiving compartment formed in said casing, means for forcing acooling and insulating fluid into said compartment, insulating cylindersplaced adjacent to and at a predetermined distance from both the innerand outer edges of said coils said cylinders having one end projectinginto said compartment, the casing being provided with an outlet for saidfluid adjacent to the other end of said cylinders. v

In witness whereof, I have hereunto set my hand this twenty-third day ofJ an., 1917.

LOCKE H. BURNHAM.

